Artificial Freshwater Research Articles

Serum Calcium and Phosphate Levels of Calcitonin Treated Freshwater Mud Eel, Amphipnous Cuchia Kept in Different Calcium Environments

Calcitonin (CT; 0.5 MRC unit/100 g body wt/day) was administered daily intraperitoneally to the freshwater mud eel, Amphipnous cuchia kept in artificial freshwater (0.8 mmol/l CaCl2), calcium-deficient freshwater (0 mmol/l CaCl2), low-calcium freshwater (0.2 mmol/l CaCl2) and calcium-rich freshwater (13.4 mmol/l CaCl2) for 15 days. Analyses of serum calcium and phosphate levels were performed on day 1, 3, 5, 10 and 15 following the start of the experiment. Administration of CT showed no effect in the fish kept in artificial freshwater and calcium-rich freshwater whereas hypocalcemia was recorded in the fish kept in calcium-deficient freshwater and low-calcium freshwater. The effect of CT on serum phosphate levels is variable. No effect (in the fish kept in artificial freshwater and calcium-rich freshwater), initial hypophosphatemia followed by hyperphosphatemia (calcium-deficient freshwater) and hyperphosphatemia (low-calcium freshwater) were noticed.

Transepithelial Potential Difference of a Single Gill Filament Isolated from the Crayfish Astacus leptodactylus Esch.: A New Method

A new method is described that allows in vitro perfusion and transepithelial electrical potential measurements of a single filament (3–5 mm long; 200 µm in diameter) isolated from the podobranch of the crayfish Astacus leptodactylus. An electrophysiological study was carried out on the preparation to validate this technique. The good physiological quality of the isolated filament preparation has been established and results of continuous measurements of the potential difference under two perfusion conditions are reported. Filaments were perfused with Van Harreveld physiological saline inside and either with Van Harreveld saline or artificial fresh water outside. Large potential differences up to 150 mV between inside and outside of the filament were recorded. When filaments were symmetrically perfused, the behavior of the electrical potential difference allowed two populations of filaments to be distinguished.

Spectrophotometric determination of periodate or iodate ions by liquid-liquid extraction as an ion-pair using tetramethylammonium iodide

A simple and accurate extractive Spectrophotometric procedure was developed for the microdetermination of periodate and iodate in aqueous media. The determination of periodate was based upon the extraction of the ion-pair formed between the periodate and tetramethylammonium iodide at pH 4 in chloroform followed by direct Spectrophotometric measurements at 509, 358 and 288 nm. The optimum concentration range evaluated by Ringbom's plot, the molar absorptivity, the Sandell's sensitivity and the stoichiometry of the formed ion-pair were critically determined. Iodate could be determined quantitively by the proposed procedure after oxidation to periodate with potassium persulphate. The effect of the diverse ions on the determination of the periodate and/or iodate by the proposed procedures was also investigated. The application of the method for the analysis of iodate or periodate in the artificial fresh water was successfully carried out.

Effect of environmental calcium levels on calcium uptake in tilapia larvae Oreochromis mossambicus

Effects of environmental calcium concentrations on the survival, growth, body calcium content and calcium uptake kinetics in developing tilapia (Oreochromis mossambicus) larvae were studied. Fertilized eggs were incubated in high- and low-calcium artificial freshwater (0.88-0.96 mmol l(-1) vs. 0.02-0.03 mmol l(-1) CaCl2 or CaSO4) until 3 days after hatching. Tilapia larvae showed similar hatching rates and wet weights in either high- or low-calcium medium, indicating neither the development nor the growth in tilapia larvae was affected by the environmental calcium levels. The body calcium content in low-calcium groups was about 90-95% that of high-calcium groups, No matter what calcium source was used (CaCl2 or CaSO4), acclimation to low calcium medium caused a stimulation of calcium uptake (measured in 0.2 mmol l(-1) calcium),i.e., 1.2-1.3 fold higher than that of high calcium groups. This enhanced calcium uptake capacity was characterized by a 50% decrease in Km and a 25% increase in Jmax. Effect of different calcium salts on calcium influx was significant only in low calcium level,i.e., calcium influx in low-CaCl2 group higher than that in low-CaSO4 group. These results suggest that tilapia larvae are able to modulate their calcium uptake mechanism to maintain normal body calcium content and growth in environments with different levels of calcium.

Effect of Salinity and Temperature on Survival and Development of Young Zebra (Dreissena polymorpha) and Quagga (Dreissena bugensis) Mussels

We reared larval zebra mussels,Dreissena polymorpha, and quagga mussels,D. bugensis, through and beyond metamorphosis (settlement) at salinities of 0–8‰. Juvenile zebra mussels gradually acclimated to 8‰ and 10‰ have been reared at these salinities for over 8 mo. Tolerance to both higher temperatures and higher salinities increases with larval age in both species (though zebra mussel embryos and larvae have a greater degree of salinity tolerance than quagga mussel embryos and larvae). Thus, only 6% of 3-day-old zebra mussel veligers survived after exposure to 4‰ for 8 additional days, whereas there was 22% survival of veligers placed in 4‰ at day 13 and grown to settlement 11 d later. Zebra mussel pediveligers, acclimated to increasing salinity in 2‰ increments beginning at day 23, continued to survive and grow in 8‰ after 5-mo exposure, though the growth rates of these juveniles were significantly less than those of juveniles reared in lower salinities. Quagga mussels did not metamorphose and settle as quickly as zebra mussel pediveligers. No quagga mussel pediveligers had settled before exposure to artificial fresh water (AFW), 2‰ 4‰, 6‰, and 8‰ on day 30. Percent settlement of these quagga mussel juveniles (based on 100% survival at the start of experiments on day 30) was 90% in AFW, 67% at 2‰, 69% at 4‰, 46% at 6‰, and 0.1% at 8‰.

Water recovery from the atmosphere

Water precisely fresh water is essential for live. The artificial fresh water production by desalting processes implies the utilization of energy. The ambient atmosphere contains a large quantity of water in the form of vapor and this endless source of water can be recovered for general use. In this paper, a method is proposed to use liquid desiccant to extract atmospheric moisture. The proposed system uses a single flat, tilted surface exposed to atmosphere as an absorber. In this paper, an analytical procedure for calculating the mass of water absorbed by the desiccant from the ambient atmospheric air in the absorber as a function of meteorological quantities and the desiccant initial conditions has been presented.

Certified reference materials (CRMs 479 and 480) for the quality control of nitrate determination in freshwater

Monitoring of freshwater and groundwater is routinely performed to control the level of contamination by a wide variety of trace and major constituents, including nitrates. In order to verify the quality of such determinations, the Standards, Measurements and Testing Programme (formerly BCR) has started a project, the first step of which was to evaluate the performance of European laboratories in an interlaboratory study and the second phase was a certification campaign of nitrate in two artificial freshwater samples. This paper presents an overview of the results of the interlaboratory evaluation and gives details of the preparation of the candidate certified reference materials (CRMs), the verification of their homogeneity and stability, the techniques used in the certification and the certified values. Two CRMs were produced: CRM 479 containing a low nitrate content (214 ± 4 µmol kg–1 or 13.3 ± 0.3 mg kg–1) and CRM 480 containing a high nitrate content (885 ± 13 µmol kg–1 or 54.9 ± 0.8 mg kg–1).

Culicoides variipennis (Diptera: Ceratopogonidae) complex in California.

Genetic relationships were examined among 24 collections, representing 23 populations of Culicoides variipennis (Coquillett) using isozyme electrophoresis of 11 protein encoding loci. The populations were collected from alkaline or fresh water larval habitats in California. Distance analysis demonstrated that C. v. occidentalis Wirth and Jones and C. v. sonorensis Wirth and Jones are genetically distinct. All C. v. occidentalis were geographically isolated from each other in highly alkaline or saline larval habitats, whereas C. v. sonorensis populations were collected from artificial freshwater habitats that were polluted with organic wastes. Higher levels of gene flow were found between C. v. sonorensis populations than from C. v. sonorensis populations to nearby C. v. occidentalis populations, indicative of genetic isolation between subspecies. Northern California C. v. sonorensis were genetically distinguishable from southern California C. v. sonorensis. The relationship between this variation and bluetongue disease epidemiology in California is discussed.

ADaM, an artificial freshwater for the culture of zooplankton

An artificial freshwater for the culture of zooplankton was developed. It guarantees the same successful long-term rearing of stock cultures and high fitness of the animals as natural water and has the advantages of standardization and reproducibility. It is suitable for a variety of zooplankton species, e.g. cladocerans, rotifers and insect larvae. This “Aachener Daphnien Medium” (ADaM) is based on synthetic sea salt and analytical grade chemicals added to deionized water. In a Daphnia magna reproduction test ADaM was compared with other synthetic media (ISO, Balk, M4). Survival and reproduction were best in M4 and ADaM.

EFFECTS OF DILUTED NATURAL WATER AND ALTERED IONIC ENVIRONMENTS ON GUSTATORY RESPONSES IN RAINBOW TROUT (ONCORHYNCHUS MYKISS)

1. The effects of adaptation to diluted natural water (NW) and various salt solutions on the gustatory responses recorded from the palatine nerve in rainbow trout (Oncorhynchus mykiss) were studied. 2. The magnitude of the response to 1 mmol l-1 l-proline (l-Pro) decreased when the perfusing NW was diluted with artificial fresh water (AFW) that maintained concentrations of major cations. AFW suppressed the responses to l-Pro by about 70 %. 3. The responses to 1 mmol l-1 l-Pro, 0.1 mmol l-1 quinine&shy;HCl (Q-HCl) and 10 nmol l-1 taurolithocholic acid (TLCA) were eliminated or reduced (to <10 %) by adapting the palate to distilled water (DW). The addition of 0.1&shy;100 mmol l-1 salts (NaCl, KCl, CaCl2, MgCl2) and choline chloride restored the gustatory responses to about 50 % of those in NW. The addition of salts to NW had no effect on the gustatory responses. 4. The gustatory responses to 5 % CO2 were similarly reduced when the palate was adapted to solutions that contained no NW (DW, AFW, 10 mmol l-1 NaCl in DW). However, the reduction was independent of salt concentration, suggesting a different transduction mechanism for CO2. 4. Tetrodotoxin (1 &micro;mol l-1) had no effect on the gustatory responses to l-Pro. 5. We conclude that NW is required and that cations alone are not sufficient to support maximal gustatory responses. The results suggest that an unknown substance(s) contained in NW plays an essential role in gustatory reception and that permeation of cations through the apical membrane of gustatory cells is not involved in gustatory transduction in rainbow trout.

Effects of calcitonin administration on serum calcium and inorganic phosphate levels of the fish, Heteropneustes fossilis, maintained either in artificial freshwater, calcium‐rich freshwater, or calcium‐deficient freshwater

AbstractFreshwater catfish, Heteropneustes fossilis, were injected daily intraperitoneally either with vehicle (0.1 ml of 0.6% NaCl/100 g body wt) or calcitonin (0.5 MRC U/100 g body wt) and maintained either in artificial freshwater, calcium‐rich freshwater, or calcium‐deficient freshwater for 10 days. The blood samples were collected on days 1, 3, 5, and 10 after initiation of the experiment, and serum calcium and inorganic phosphate levels were analysed.(i) Artificial freshwater: There is no change in the serum calcium and inorganic phosphate levels of calcitonin‐injected fish.(ii) Calcium‐rich freshwater: In vehicle‐injected fish there is a progressive hypercalcemia from day 1 to day 5. On day 10 the value decreases but it is still hypercalcemic. No change has been noticed in the serum calcium level of calcitonin‐treated fish. In vehicle‐treated fish the serum inorganic phosphate level indicates a decrease on day 10. The serum inorganic phosphate level of calcitonin‐treated specimens exhibits no change.(iii) Calcium‐deficient freshwater: There is a progressive decrease from day 1 to day 3 in serum calcium level of vehicle‐injected fish. Thereafter, from day 5 the level increases thus resulting in hypercalcemia on day 10. Calcitonin treatment to the fish evokes a decrease in the serum calcium level from day 1 to day 3. Thereafter a significant hypercalcemia is recorded on day 5 and day 10. In vehicle‐injected fish the serum inorganic phosphate levels decrease from day 3 to day 5. However, the value increases on day 10. Serum inorganic phosphate level of calcitonin‐treated fish exhibits a decrease on day 1. Thereafter, it rises progressively from day 3 to day 10. © 1993 Wiley‐Liss, Inc.

The effect of Cu(II) on the electro-olfactogram (EOG) of the Atlantic salmon ( Salmo salar L) in artificial freshwater of varying inorganic carbon concentrations

The effect of inorganic copper species was studied by recording the receptor potential, electro-olfactogram (EOG), from the olfactory epithelium of Atlantic salmon ( Salmo salar L). In a series of experiments, the olfactory organ was irrigated with aqueous copper solutions with concentrations of the free cupric ion (Cu 2+) ranging from 0.2 to 9.7 μ M. The diverse copper species were created by varying the amount of bicarbonate (NaHCO 3) in artificial freshwater solutions of equal total copper concentrations. In general, these copper solutions induced a slow depolarization of the baseline followed by a hyperpolarization. The amplitudes of these variations in baseline potentials increased with increasing concentrations of Cu 2+ ion, i.e., decreasing concentrations of NaHCO 3. Stimulating the olfactory epithelium with l-alanine during the copper exposure evoked atypical EOG responses. The amplitudes and form of the EOGs changed drastically with increasing Cu 2+ concentrations, with significant correlation between the reduction in EOG amplitudes and the Cu 2+ concentration. The results indicate that among the copper species tested the toxic effect is caused mainly by the dissolved Cu 2+ ion. The results also suggest that the Cu 2+ ion exerts its toxic effects on the transduction mechanisms of the olfactory receptor cells. The different EOG profiles obtained in response to varying Cu 2+ concentrations indicate that this ion affects the transduction mechanisms at different stages.

Effect of vitamin D 3 administration on the serum calcium and inorganic phosphate levels of the freshwater catfish, Heteropneustes fossilis, maintained in artificial fresh water, calcium-rich fresh water, and calcium-deficient fresh water

Freshwater catfish, Heteropneustes fossilis, were injected daily intraperitoneally either with vehicle (0.05 ml of 95% ethanol/100 g body wt) or vitamin D 3 (50 I.U./100 g body wt) and maintained in artificial fresh water, calcium-rich fresh water, or calcium-deficient fresh water for 10 days. The specimens were sacrificed on Days 1, 3, 5, and 10 after initiation of the experiment. The blood samples were collected on these intervals and serum calcium and inorganic phosphate levels were analyzed. Vitamin D 3 induced hypercalcemia and hyperphosphatemia in the freshwater catfish, H. fossilis. These effects of vitamin D 3 are not dependent upon the calcium concentration of the different ambient media used in this study.

Dominant parasites of fish in Georgia, USSR

Intensive fish breeding in artificial freshwater reservoirs and ponds is often accompanied by epidemics of invasive parasitic diseases. In the USSR, much attention is given to the study of fish parasites and diseases, revealing a range of protozoan and helminth parasites that can cause significant economic losses to the fish industry (Table I ; Refs 1–5)

Gill morphology and sodium influx in the rainbow trout (Salmo gairdneri) acclimated to artificial freshwater environments

AbstractBranchial sodium uptake was measured across secondary lamellae (SL) using the isolated‐perfused head preparation. This study was correlated with histological examination.Freshwater trout, Salmo gairdneri, were exposed to various artificial media: distilled water (DW), fresh water (FW: NaCl &lt; 200 μl/1; Ca++ = 1.5 mM/1), FW + 5 mM CaCl2 and FW + 10 mM CaCl2. These environments altered the number and forms of “chloride cells” (CC) located in SL and were related to changes in maximal transport rate of Na+. An increase in a specific type of CC (round) was associated with an increase in Vmax, and a decrease in round cells was associated with a decrease in Vmax.Relative to FW, exposure to DW increased the density of round cells, FW + 5 mM CaCl2 had no effect, and FW + 10 mM CaCl2 produced an initial degeneration of CC followed by restoration and increase in protruding round cells.We conclude that secondary lamellar chloride cells play an important role in Na+ uptake.

Ionic permeabilities of the gill lamina cuticle of the crayfish, Astacus leptodactylus (E).

The cuticle of the gill lamina of the crayfish Astacus leptodactylus (E), mechanically isolated, was mounted in an Ussing chamber and examined for its electrical properties. The cuticle of the gill lamina obtained from exuviae had similar properties. When perfused with artificial fresh water (AFW) outside and Van Harreveld solution (VH) inside, the transcuticular potential Voi was negative with respect to the inside, and close to the equilibrium potential for Cl- (ECl-). CH3COO-, HCO3-, SO4(2-) and cations (Na+, K+, Ca2+, Mg2+ and NH4+) behaved as impermeant ions with respect to Cl-. A decrease of pH (brought about with CO2) from 8.5 to 6.0 in AFW, VH or both had no effect on the potential. The cuticle area specific conductance was 20-30 mS/cm2 when superfused with AFW outside and VH inside. The conductance decreased linearly with log [Cl-] when Cl- was replaced by CH3COO-. Rectification was obvious when internal Cl- was reduced to 5 mmol/l. The Cl- selectivity of the cuticle could also be demonstrated in perfusing the cuticle with a single salt (NaCl, KCl, CaCl2, MgCl2 or LaCl3) and in diluting that salt on one side of the preparation or in replacing Cl- by CH3COO-, SO4(2-) and HCO3-. The potential changed almost linearly with log [Cl-] and was close to ECl-. The inner face of the cuticle was found to be slightly less selective than the outer face. The relative permeabilities were calculated to be: PCl- = 1, PNa+ = 0.001, PHCO3- = 0.0006, PCH3COO- = 0.0002. The dilution of a Cl- -free salt resulted in a cationic potential. The relative permeabilities of cations (NH4+, K+, Na+, Ca2+ and Mg2+) were found to range within a factor 2. The permeability of the cuticle to HCO3-, CH3COO- and SO4(2-) was 2-5 times lower. The cuticle conductance was linearly related to the activity of the salt perfusing the two sides of the preparation at equal concentrations. The molar area specific conductance to chloride salts was 14 (mS/cm2)/(mmol/l). That of Cl- -free salts ranged from 1 to 20 (microS/cm2)/(mmol/l) depending on the salt used. It was deduced that PCl- is 2 X 10(-3) cm/s and that all the other ions tested have permeabilities of 10(-7)-10(-6) cm/s. With large intensity current pulses the cuticle exhibited rectifying properties and an asymmetrical behaviour. Increasing the pH of the perfusing solution reduced the transcuticular potential established with a Cl- gradient.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of pH, iron and humic acid on the estuarine behaviour of phosphate

Abstract Processes controlling the estuarine behaviour of phosphate have been investigated using a model estuarine mixing system. Different phosphate vs. salinity profiles were produced when seawater was added to artificial freshwaters of various pH and concentrations of iron, humic acid and phosphate. These profiles simulate observed phosphate behaviour in real estuaries, and are the result of a balance between phosphate adsorption onto colloidal iron phases in the freshwater, subsequent colloidal aggregation, phosphate desorption, and dilution with seawater. Changes of pH have a larger effect on phosphate behaviour than do changes of salinity.

Biodegradation and photolysis of pentachlorophenol in artificial freshwater streams.

The biodegradation, photolysis, and adsorption of pentachlorophenol (PCP) in outdoor, aquatic environments were examined with man-made channels built by the U.S. Environmental Protection Agency at a field station on the Mississippi River near Monticello, Minn. Four channels were used, each channel being approximately 520 m long and receiving river water that flowed through the channels for about 10 h before reentering the river. The channels were dosed continuously during the summer of 1982 with various concentrations of PCP (approximately 0, 48, 144, and 432 micrograms/liter). We monitored the biotic and abiotic degradation of PCP in these channels for approximately 16 weeks. Photolysis of PCP was rapid at the water surface, but greatly attenuated with depth. Depending on sunlight conditions, photolysis accounted for a 5 to 28% decline in initial PCP concentration. Adsorption of PCP by sediment and uptake by biota accounted for less than 15% and probably less than 5% in unacclimated water. Microbial degradation of PCP became significant about 3 weeks after the initiation of dosing and eventually became the primary mechanism of PCP removal, accounting for a 26 to 46% (dose-dependent) decline in initial PCP. Most of the PCP-mineralizing microorganisms that developed in the channels were either attached to surfaces (e.g., rocks and macrophytes) or associated with surface sediments. Total bacterial numbers (direct microscopic counts) in the various channels were not affected significantly by PCP concentrations of micrograms per liter. Numerous strains of bacteria able to grow at the expense of PCP were isolated from the adapted channels. The experiments reported here will help predict the responses of flowing aquatic ecosystems to contamination by biocides such as pentachlorophenol.

ECOLOGICAL EFFECTS OF OIL-DISPERSANT MIXTURES IN FRESH WATER

ABSTRACT A series of spills using oil and dispersant was begun July 5, 1978 in a set of artificial freshwater ponds. Prior to the spills, the ponds had been allowed to stabilize and the water as well as a number of biological components including zooplankton, phytoplankton, bacteria, and fungi was regularly monitored. These parameters also were determined regularly after the spill as was the distribution of the stressing agents. The short-term results, encompassing the observations made for 55 days following the spills, indicate that the oil-dispersant mixture affects the zooplankton, phytoplankton, bacteria, fungi, and dissolved oxygen to a greater degree than oil alone. Also, in the oil-dispersant ponds there was an enhancement of the dissolved reactive silica values relative to the oiled and control ponds.

Effects of inhibitors on ion fluxes, trans-gill potential and pH regulation in freshwater blue crabs,Callinectes sapidus (Rathbun)

1. The effects of externally applied amiloride and thiocyanate, and injected acetazolamide on trans-gill potential, blood pH, branchial ion fluxes, and rates of compensation of hypercapnic acidosis were studied in a freshwater population of the blue crab,Callinectes sapidus. 2. Amiloride inhibited Na+ fluxes without affecting Cl− fluxes, and SCN− blocked Cl− fluxes with only a slight effect upon Na+ fluxes at high SCN− concentration. 3. There was no significant effect of Na-free water on Cl− fluxes, nor Cl-free water on Na+ fluxes. 4. Injected acetazolamide inhibited both influx and efflux of Na+, but stimulated Cl− efflux. 5. Neither external SCN−, external amiloride, nor injected acetazolamide affected blood pH or trans-gill potential in crabs resting in normally aerated water. 6. External SCN− increased the rate at which external hypercapnia was compensated for by increased HCO3− in the blood, but amiloride had no effect. The net rate of whole animal base excretion was about 38 μEq·100 g−1·h−1 whether in natural freshwater, artificial Cl-free medium, freshwater plus SCN−, or freshwater plus amiloride. 7. The majority of Na+ and Cl− fluxes appear to be independent, with a large self-exchange component. Some of the results support the presence of Na+/H+ (NH4+) and Cl−/HCO3− components, but these exchanges may be only a very small part of the balance of Na+ and Cl− fluxes.